Modern electronic marketplaces allow consumers to search and purchase a variety of items online. To facilitate informed decisions by consumers with respect to a particular item, a list of offers for the item from different sellers may be collected and provided to consumers for comparison purposes. Often times, offers may include erroneous, fraudulent, or otherwise undesirable information. For example, a seller may unintentionally put in an offer with a mistake in the price or description of the item. As another example, a seller may provide a deceptive lowball offer in order to get to the top of the offer list. Such anomalies may negatively affect a consumer's experience and hurt the bottom line.